Richard birkholz



(No Model.)

v S R. BIRKH0LZ.

ROLL FOR GRINDING MILLS 291 Patented Apr. 18

WITNESSES By Attorney N. PETERS. Phommho hw, washin wn, D. c.

,UNITEI) STATES PATENT OFFICE."

RICHARD BIRKHOLZ, OF MILWAUKEE, WISCONSIN, ASSIGNOR TO EDWARD P. ALLIS, OF SAME PLACE.

ROLL FOR GRINDING-MILLS.

SPECIFICATION forming part of LettersPatent No. 256,28, dated April 18, 1882.

Application filed December 6, 1881. (No model.)

To all whom it may concern:

Be it known that I, RICHARD BIRKHOLZ, of Milwaukee, in the county of Milwaukee and State of Wisconsin, have invented certain Improvemenls in Rolls for Grinding-Mills, of

which the following is a specification.

My invention relates to that class of grinding-rolls now in general use in flouring-mills, in which a tubular body or shell of porcelain to is mounted on and carried by a central driving-shaft. The requirements are that the surface of the porcelain shall run with the highest attainable degree of accuracy, that the porcelain shall be free from danger of displace, 1:5 went under the strain and pressure encountered in action, that it shall be free from liability to fracture when being fastened in place or when heated by use, that it shall be capable of ready removal from the shaft, and that' it shall be as free as possible from a tendency to heat and remain heated when in action. Owing to the extremely brittle and friable character of the porcelain, it is of the greatest importance that the formation of incisions, recesses, and angles in the porcelain shall be avoided, itbeing found-in pr ctice that when they exist the porcelain will, upon receiving the slightest unequal or excessive strain,be fractured, the fracture beginning in the angle 0 or recess.

Various methods of securing the porcelain body have been used with different degrees of success; but all are foundopen to serious objection. One plan was that of having the square 5 or flat ends of the porcelain bodyheld between flat plates or collars on' the shaft. Practice has shown that this would not retain the shell in its concentric position unless an excessive and highly dangerous pressure was applied,

0 and therefore the space around the shaft within the shell was filled with cement, which added to the expense and weight, rendered the removal of the body practically impossible, and caused the rollto heat easily and remain heated,

4 5 thereby impairing the grinding action and endangering a fracture of the. rolls. Another plan proposed was that of clamping the body between plates having conical hubs entering the center of the body. The conical hubs, if

fitted to be of service, were very liable to split the porcelain, a very slight heating and expansion of the iron being fatal. Another plan proposed was that of beveling the ends of the porcelain body and forming therein numerous angular recesses or depressions, and then clamping the same between plates or collars provided with beveled faces and with studs to enter the recesses. A complicated and expensive construction of the clamping-plates was shown, and an expensive and unreliable system of keys suggested for securing them in place. Cement was to be introduced in the center to hold the body against vradialdisplacement. This plan is expensive. Itiuvolves the use of the dangerous and expensive recesses in the porcelain, and it renders the accurate adjustment by the keyszpractically impossible.

My invention consists in providing the porcelaiu body with smooth, unbroken end surfaces beveled off around the outer edge, in combiuin g therewith corresponding end plates mounted on the shaft and provided with unbroken inner faces recessed or beveled inward to fit the ends of the porcelain, and in securing said plates by tie-rods or equivalent means against the porcelain with asufficient pressure to sustain and carry the same by friction. The beveling of the faces causes the parts to be accurately centered and prevents the body from being displaced or forced out of position. The engagement of the beveled faces over and around the porcelain compresses and binds the same together so as to avoid fracture. By seating the collars or end plates directly and close- 1y upon the shaft, accuracy of adjustment is insured and the diffieulties and dangers incident to intermediate keys, collars, &c., avoided. Instead of tillingor'closingtheinteriorspace of the body of the roll, I leave the same vacant and perforate the end plates, as at h, permitting air to circulate freely through the interior and preventing the body from heating. In order to give additional friction between the body and end plates, I introduce washers of paper or equivalent material, constructed as hereinafter described.

Referring to the accompanying drawings, Figure 1 represents a side elevation of my roll, a portion being shown in section on the line 00 a", Fig. Fig. 2 is an end elevation of the ICC roll, a portion being shown in section in the line 3 3 Fig. 1.

A represents the central shaft or roller; B, the hollow cylindrical body, of porcelain or eqnivalentmaterial,madecompleteinonepicce; U G, the end plates or collars; and D D, the tie rods or bolts passin glon gitudinall y through the body and through the end plates, drawing the latter against the body.

Each end of the porcelain shell or body is squared or flattened around the center, as represented at a, and the outer edge beveled or tapered, as shown at b, the end of the body having,iu other words, the form of a truncated cone. It is to be particularly noted that the end surfaces ofthe roll are continuous, smooth, and unbroken, and that there are no angles or corners therein. Each of the end plates has its inner side recessed and provided, as shown, with the fiat and beveled faces 0 (1, adapted to fit snugly the end faces, a I), of the roll.

The tie-rods are provided at one end with heads and squared necks to prevent them from turning, and at the opposite end with nuts, by turning which the rods are caused to draw the two end plates with great firmness against the noted that, as the end of the roll is seated in and surrounded by the conicai recessed plate, the plate applies more or less compression to the body, binding the same together and enabling it to resist severe strains without cracking or breaking.

In order to increase the friction and avoid dangers to the porcelain lllllle event of an un even pressure being applied, the washers E, of paper or like material, are seated between the porcelain and theend plates,as shown. Itispreferred to have these washers bear between both theinclincdand theflatsurfaces. Thisisbestseon red by constructing the washers, as shown in Fig. 3, by providing a ring of paper of suitable ,size and making radial incisions in its inner edge, as shown. This permits the packing to bond and assume an angular form in cross-section, as shown in Fig. 1. The end plates or collars are seated directly upon the shaft and secured by splines, as shown, or equivalent devices, to prevent them from turning thereon. While it is preferred to use the tie-rods, other suitable means adapted to force the end plates inward positively may be used.

As to any matters and things herein shown and described but not specifically claimed, the right is reserved to make the same the subjectmatter of future application.

Having thus described myinvcntion, what I claim is- 1. In a grindingroll, the tubular porcelain body having the smooth, unbroken ends with beveled faces, in combination with the recessed end plates having corresponding unbroken surfaces, and the meansibrdrawing said plates firmlyagainsttheendsofthebody,asdcscribed 7 and shown, whereby the body is maintained in a central position and prevented from fracturmg.

2. The combination of the shaft, the end plates mounted and secured against rotation upon the shaft and provided with smooth tapered recesses, the porcelain, body having smooth tapered end, and the tie-rods extended through the body and the end platcs,as shown.

3. As a new article of manufacture, a tubu- 8o lar cylindrical porcelain body having on its end the unbroken, squared, and beveled surfaces a b, as shown and described.

4. TlJOCOlIll;lllt1llOll oftheporcelainbodyhaving the flat and beveled surfaces at its ends, the smooth recessed end plates, the fastening devices, and the washers inserted between the body and end plates and bearing between both the flat and the beveled surfaces, as shown.

5'. The porcelain roll having smgpth conical 9o ends, seated in and driven by friotional communication with correspondingly recessed end plates urged forcibly toward the roll, substant ally as described and shown.

' RICHARD BIRKHOLZ. Witnesses:

FERNANDO O. PATTERSON, JOHN JEROME RYNEAL. 

